A motor controller estimates an initial position of a magnetic pole of a rotor of a brushless DC motor in an inductive sensing scheme. The motor controller controls a drive circuit to apply an AC voltage to a stator winding at a first energization angle, and subsequently to apply an AC voltage to the stator winding at a second energization angle before a residual current flowing through the stator winding returns to zero. At each energization angle, the motor controller corrects a peak value of a current in the stator winding based on the residual current detected immediately before a voltage is applied to the stator winding or at a time when voltage application to the stator winding is started. Based on the corrected peak value, the control circuit estimates the initial position of the magnetic pole of the rotor.

The present disclosure is directed to a permanent magnet motor control method and system. A new structure configuration of a permanent magnet motor has a rotor with two or more permanent magnets attached thereon, a stator wound in a Y topology with three coils (windings) arranged at 120 degree among one another, and a neutral point of the wound stator wired in a manner that the voltage at the neutral point may be detected in substantially real time. The detected neutral point voltages are analyzed together with the associated vectors of the excitation current provided to the windings of the stator to determine a speed of the rotor. The determined speed of the rotor is used for vector control.

The present disclosure is directed to a permanent magnet motor control method and system. A new structure configuration of a permanent magnet motor has a rotor with two or more permanent magnets attached thereon, a stator wound in a Y topology with three coils (windings) arranged at 120 degree among one another, and a neutral point of the wound stator wired in a manner that the voltage at the neutral point may be detected in substantially real time. The detected neutral point voltages are analyzed together with the associated vectors of the excitation current provided to the windings of the stator to determine a speed of the rotor. The determined speed of the rotor is used for vector control.

A magnetic pole initial position detection device includes: a direct-current excitation command generation section configured to generate a first command for causing a constant excitation current with a current phase fixed to a first phase to flow through the synchronous motor; a torque-zero determination section configured to determine whether a torque generated in the rotor of the synchronous motor is zero when the excitation current based on the first command flows through the synchronous motor; and a magnetic pole initial position acquisition section configured to acquire the magnetic pole initial position of the rotor of the synchronous motor on a basis of a rotor actual position at or near a point in time when the torque-zero determination section determines that the torque is zero; a number of pole pairs of the synchronous motor; and an excitation phase during direct-current excitation under the first command.

A method and apparatus for self-commissioning a bearingless-motor drive, which includes a bearingless motor and a control unit of the bearingless motor are disclosed. The motor includes at least one winding and at least one permanent magnet. The method includes generating a magnetic model, the magnetic model including a plurality of constant parameters; supplying, while the movable part remains standstill, to the at least one winding at least two unequal currents; measuring, with a magnetic sensor, flux linkages caused by said at least two unequal currents, respectively; calculating, with the magnetic model, flux linkages by inputting to the magnetic model current values equal to the currents supplied to the at least one winding; and fitting, with a least-squares fitting algorithm, at least one constant parameter in the magnetic model such that the difference between the measured and calculated flux linkages will be minimized.

The invention relates to a method and device for determining the position angle of a rotor (2) in an electric synchronous machine (1). The device is designed to comprise: a voltage generator (12) for generating electrical voltage pulses at angles in a coordinate system fixed in respect of the stator when the rotor (2) is stationary; a measuring device (14) for measuring any electrical current value returning to the electrical voltage pulses generated by the voltage generator (12); and a computing device (16), which is designed: to store a current signal curve of the current values measured; to generate a zero-mean current signal curve by shifting the current signal curve or the measured current values; to compute an integral function (83) of the zero-mean current signal curve; andto determine the position angle of the rotor (2) on the basis of the computed integral function (83).

The present invention relates to a circuit arrangement and to a method for sensorless commutation of electronically commutated synchronous machines such as, for example, EC motors, wherein the terminal values at the connection terminals of the synchronous machine are processed by means of a rotor position estimator based on the EMF of the synchronous machine and of a known motor model preferably in a PLL structure for sensorless determination of rotor position information, and said information is used for commutation.

The present invention relates to a circuit arrangement and to a method for sensorless commutation of electronically commutated synchronous machines such as, for example, EC motors, wherein the terminal values at the connection terminals of the synchronous machine are processed by means of a rotor position estimator based on the EMF of the synchronous machine and of a known motor model preferably in a PLL structure for sensorless determination of rotor position information, and said information is used for commutation.

A motor controller includes current measurement circuitry and estimation circuitry. The current measurement circuitry is adapted to be coupled to a motor, and configured to measure current in the motor. The estimation circuitry is coupled to the current measurement circuitry, and includes a memory, current computation circuitry, and summation circuitry. The memory stores coefficients of a function for estimating current related to variation of inductance of the motor. The current computation circuitry is coupled to the memory, and is configured to compute a compensation current value based on the coefficients. The summation circuitry is coupled to the current compensation circuitry, and is configured to generate a position error signal by subtracting the compensation current value from a measured current value generated by the current measurement circuitry.

A motor controller includes current measurement circuitry and estimation circuitry. The current measurement circuitry is adapted to be coupled to a motor, and configured to measure current in the motor. The estimation circuitry is coupled to the current measurement circuitry, and includes a memory, current computation circuitry, and summation circuitry. The memory stores coefficients of a function for estimating current related to variation of inductance of the motor. The current computation circuitry is coupled to the memory, and is configured to compute a compensation current value based on the coefficients. The summation circuitry is coupled to the current compensation circuitry, and is configured to generate a position error signal by subtracting the compensation current value from a measured current value generated by the current measurement circuitry.